The present disclosure relates generally to an imaging process. More specifically, the disclosure relates to an application system for applying a duplex process wherein single pass duplexing is achieved using more than one integrated image marking engine.
Ink jet printing systems utilizing intermediate transfer ink jet recording methods, such as that disclosed in U.S. Pat. No. 5,389,958 (the '958 patent) entitled IMAGING PROCESS and assigned to the assignee of the present application, is an example of an indirect or offset printing architecture that utilizes phase change ink. A release agent application defining an intermediate transfer surface is applied by a wicking pad that is housed within an applicator apparatus. Prior to imaging, the applicator is raised into contact with the rotating drum to apply or replenish the liquid intermediate transfer surface.
Once the liquid intermediate transfer surface has been applied, the applicator is retracted and the print head ejects drops of ink to form the ink image on the liquid intermediate transfer surface. The ink is applied in molten form, having been melted from its solid state form. The ink image solidifies on the liquid intermediate transfer surface by cooling to a malleable solid intermediate state as the drum continues to rotate. When the imaging has been completed, a transfer roller is moved into contact with the drum to form a pressurized transfer nip between the roller and the curved surface of the intermediate transfer surface/drum. A final receiving substrate, such as a sheet of media, is then fed into the transfer nip and the ink image is transferred to the final receiving substrate.
To provide acceptable image transfer and final image quality, an appropriate combination of pressure and temperature must be applied to the ink image on the final receiving substrate. U.S. Pat. No. 6,196,675 entitled APPARATUS AND METHOD FOR IMAGE FUSING and assigned to the assignee of the present application (the '675 patent) discloses a roller for fixing an ink image on a final receiving substrate. An embodiment of the roller is described in the context of an offset ink jet printing apparatus similar to the one described in the '958 patent. In this embodiment, an apparatus and related method for improved image fusing in an ink jet printing system are provided. An ink image is transferred to a final receiving substrate by passing the substrate through a transfer nip. The substrate and ink image are then passed through a fusing nip that fuses the ink image into the final receiving substrate. Utilizing separate image transfer and image fusing operations allows improved image fusing and faster print speeds.
Various apparatuses for recording images on sheets have heretofore been put into practical use. For example, there are copying apparatuses of the type in which the images of originals are recorded on sheets through a photosensitive medium or the like, and printers in which image information transformed into an electrical signal is reproduced as an image on a sheet by an impact system (the type system, the wire dot system or the like) or a non-impact system (the thermosensitive system, the ink jet system, the laser beam system or the like).
The present exemplary embodiments relate to a plurality of image marking engines or image recording apparatuses, and media feeder modules, providing a multifunctional and expandable printing system. It finds particular application in conjunction with integrated printing modules having several marking engines, each having customizable or different printing capabilities, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
It is common practice to record images not only on one surface of the sheet, but also on both surfaces of a sheet. Copying or printing on both sides of a sheet decreases the number of sheets used from the viewpoint of saving of resources or filing space. In this regard as well, a system has been put into practical use whereby sheets having images recorded on a first surface thereof are once accumulated and after the recording on the first surface is completed, the accumulated sheets are then fed and images are recorded on a second surface thereof. However, this system is efficient when many sheets having a record of the same content are to be prepared, but is very inefficient when many sheets having different records on both surfaces thereof are to be prepared. That is, when pages 1, 2, 3, 4, . . . are to be prepared, odd pages, i.e. pages 1, 3, 5, . . . , must first be recorded on the first surface of the respective sheets, and then these sheets must be fed again and even pages 2, 4, 6, . . . must be recorded on the second surface of the respective sheets. If, during the second feeding, multiplex feeding or jam of sheets should occur, the combination of the front and back pages may become mixed, thereby necessitating recording be done over again from the beginning. To avoid this, recording may be effected on each sheet in such a manner that the front and back surfaces of each sheet provide the front and back pages, respectively, but this takes time (reduction in ppm) for the refeeding of sheets and the efficiency is reduced.
In recent years, the demand for even higher productivity and speed has been required of these image recording apparatuses. However, the respective systems have their own media feed and image processing speed limits and if an attempt is made to provide higher speeds, numerous problems will occur and/or larger and more bulky apparatuses must be used to meet the higher speed demands. The larger and bulkier apparatuses, i.e. high speed printers, typically represent a very expensive and uneconomical apparatus. The expense of these apparatuses along with their inherent complexity can only be justified by the small percentage of extremely high volume printing customers.
U.S. Pat. Nos. 4,591,884; 5,208,640; and U.S. Pat. No. 5,041,866 are incorporated by reference as background information.
Currently duplex print quality issues associated with a standard ink jet duplex print processes are addressed via reduced duplex productivity (reduced ppm). This is best exemplified in a slowdown algorithm that can be used wherein, depending on the image content, the duplex speed is either 24 ppm or 38 ppm while the simplex speed is 50 ppm.
For a series of integrated printers, using solid ink jet (SIJ) print engines, this disclosure proposes a duplex print mode where one engine exclusively prints the first side of duplex and another engine prints the second side of the duplex. This can increase the duplex print speed, i.e. to 38 ppm, independent of image content. Furthermore, the duplex image quality will be improved because the configuration enables maintenance of one of the print engine's transfix roll for gloss, offset, and roller ghosting while at the same time, the other print engine's transfix roll can be run so that no drum touches are achieved thus transferring no oil to the backside of the sheet which is the known issue for duplex dropout.